首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
基于盐酸羟胺在弱酸性介质中被KIO4 氧化产生H2 O2 , H2 O2 与Luminol 发生化学发光反应,设计了流动注射—化学发光测定盐酸羟胺的方法. 线性范围为0-03 ~1-0μg/mL; 检出限为6-7ng/mL; RSD 为3-6 % . 测定含盐酸羟胺试样, 回收率为95 % ~98 % .  相似文献   

2.
新邻二氮菲分光光度法测定天然水中微量铁   总被引:2,自引:0,他引:2  
本文研究了用固体硫酸钾铝-盐酸羟胺代替醋酸钠溶液控制体系的pH值,对邻二氮菲分光光度法测定水中微量铁进行了新的改进。克服了原光度法[1]中空白对照显色较深,相对标准偏差较大等缺点。提高了方法的灵敏度和准确度,方法简便、快速。标准偏差为0.064,变异系数2.20%,回收率为96.0%~100.5%。  相似文献   

3.
肟化法测定盐酸青藤碱   总被引:4,自引:0,他引:4  
应用肟化法简便快速地测定了盐酸青藤碱,选择了合适的水浴温度和加热时间,实验测定的RSD小于0.7%,并与汞液滴定法、酰化法和克氏定氮法的测定结果对照,结果表明肟化法具有较高的准确度和精密度。  相似文献   

4.
3,4,5-三甲氧苯甲醛是制TMP的关键中间体,用苯酚先磺化再溴化,再经甲氧基化、甲酰化、甲基化4步反应合成。每步产率分别为77.7%,76.0%,41.0%和93.0%,总收率为22.5%。对2,6-二甲氧基苯酚的Vilsmeier-Haack甲酰化反应,Duff反应以及Reimer-Tiemann反应等可能的甲酰化方法进行了研究。  相似文献   

5.
该文对工业糠醛检测方法进行了研究。着重阐述了盐酸羟胺肟化法(国标法)、气相色谱法、电位滴定法、紫外分光光度法测定糠醛的原理以及优缺点。  相似文献   

6.
报道了一种反相HPLC方法对几种芳烃衍生物型捕收剂的分离和测定.该法借助色谱柱LiChroCART100RP18(5μm),流动相:甲醇-水-5%H3PO4-5%H2SO4(45∶55∶4∶0.5,体积分数)和紫外检测器在285nm波长下进行.在0.0005~0.01g/L浓度范围内,方法的相对标准偏差为1.1%~2.4%.水杨羟肟,苯并三唑,水杨醛肟,水杨酸,铜铁灵等的检出限分别为1.0×10-6,0.2×10-6,1.0×10-6,5.0×10-6和6.0×10-6g/L,所研制的方法已应用于矿物浮选过程实际样品的分析.  相似文献   

7.
3,4,5—三甲氧基苯甲醛的合成   总被引:1,自引:0,他引:1  
3,4,5-三甲氧苯甲醛是制TMP的关键中间体,用苯酚先磺化再溴化,再经甲氧基化、甲酰化、甲基化4步反应合成。每步产率分别为77.7%,76.0%,41.0%和93.0%,总收率为22.5%,对2,6-二甲氧基苯酚的Vilsmeier-Haack甲酰化反应,Duff反应以及Reimer-Teimann反应等可能的甲酰化方法进行了研究。  相似文献   

8.
利用甲醛与盐酸羟胺反应生成甲肟,通过甲肟的还原波测定甲醛的量,甲醛浓度与峰电流在10~(-4)~10~(-5) mol/L间成线性关系,最低检出限为1×10~(-5) mol/L,相对标准偏差在2.1%以下。  相似文献   

9.
研究了将五环[5.4.0.02,6.03,10.05,9]十一烷-8,11-二肟2和五环[6.3.0.02,6.03,10.05,9]十一烷-4,7-二肟8氧化为硝基的反应,实验表明,这两种肟的直接氧化未能成功.对2,最合适的方法是用N-溴代琥珀酰亚胺(NBS)作为氧化剂;对8,最合适的方法是用溴和臭氧分步氧化.  相似文献   

10.
生长调节物质对丹参叶片脱分化及根芽分化的效应   总被引:11,自引:1,他引:11  
生长调节物质对丹参叶片脱分化及根芽分化效应的研究结果表明:(1)0.5~5.0mg/L2,4-D,0.1~0.5mg/LNAA0.5~1.5mg/LIBA或0.2~1.0mg/L4PU-30诱导叶片的脱分化率高达97%~1000%。(2)0.1~0.5mg/LNAA或0.5~2.0mg/IBA诱导芽化率为93%~100%,3种细胞分裂素中,4PU-30对叶片芽化最有效,6-BA和KT次之。(3)随  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

18.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号